This invention is related generally to the art of measuring levels of electromagnetic radiation, such as nuclear (alpha and beta rays) and X-radiation (gamma rays), and more specifically relates to techniques for compensating for the dead-time of ionization type detectors.
One such detector that is widely used in radiation rate and dose measurement instruments is the Geiger-Muller tube. Such tubes contain a pair of spaced apart electrodes within an envelope that contains a gas which breaks down or ionizes after receiving a threshold level of nuclear or similar types of radiation. The ionization causes an instantaneous pulse to be generated by the tube, and it is the practice for rate and dose measuring instruments to count these pulses in some manner as an indication of the radiation level. One source of error in such instruments is a dead-time that exists in the Geiger-Muller tube immediately following the pulse generating ionization. That is, if enough radiation is present to ionize the gas within the tube an instant after the pulse is generated, the tube will not respond and that radiation indicating pulse is lost.
Therefore, it is a principal object of the present invention to provide a technique using such detectors that corrects the measurement for the detector dead-time.
It is another object of the present invention to provide a digital measuring circuit that is easily calibratible.